Diagnosing what's draining your battery can be very frustrating. I put together this email after helping my daughter find the source of battery drain in her 2003 Highlander. I suspect this will be helpful to many followers of this forum.
This won't likely help diagnose what's draining your trailer battery since we all lean very quickly, there's a lot of stuff connected to your trailer battery that doesn't run through your circuit breakers or fuses. If you're willing to spend the time, you will learn quite a bit on how to diagnose electrical problems with much less "mystery".
Battery Parasitic Draw Diagnosis
How to diagnose why your battery keeps going dead:
Though lengthy, all three videos are worth watching. You'll
learn a lot about how to diagnose car electrical problems.
The long video has a lot of talking but every once in a while he says something you don't want
to miss.
New cars anything over .2 amps is parasitic draw, because of computers.
Older cars anything over .05 amps will be parasitic.
Battery Parasitic Draw (short video) 4:47
How to connect the multimeter
Pull fuses to isolate. - on new cars this can cause the computer to
wake up and you may have to wait 30 minutes for it to go back to sleep.
Pull relays to isolate - on new cars this can cause the computer to
wake up and you may have to wait 30 minutes for it to go back to sleep.
Long video 33:00
very long video but worth watching:
5:43 - charge battery weak battery will cause lots of problems
connect clamp on amp meter
28:46 how to connect multimeter without clamp
/////
At 13:24 in this video the technician measures the voltage drop across a fuse and then
using a lookup table (below) determines the current flowing through that fuse. This is how
He determines which circuit is exhibiting parasitic draw on the battery.
Lookup Table - Amperage through a fuse by measuring the Voltage drop across a fuse:
better table - https://www.powerprobe.com/resource/20240904232955310.pdf
fuse types:
parasitic
Dustin
This won't likely help diagnose what's draining your trailer battery since we all lean very quickly, there's a lot of stuff connected to your trailer battery that doesn't run through your circuit breakers or fuses. If you're willing to spend the time, you will learn quite a bit on how to diagnose electrical problems with much less "mystery".
Battery Parasitic Draw Diagnosis
How to diagnose why your battery keeps going dead:
Though lengthy, all three videos are worth watching. You'll
learn a lot about how to diagnose car electrical problems.
The long video has a lot of talking but every once in a while he says something you don't want
to miss.
New cars anything over .2 amps is parasitic draw, because of computers.
Older cars anything over .05 amps will be parasitic.
Battery Parasitic Draw (short video) 4:47
How to connect the multimeter
Pull fuses to isolate. - on new cars this can cause the computer to
wake up and you may have to wait 30 minutes for it to go back to sleep.
Pull relays to isolate - on new cars this can cause the computer to
wake up and you may have to wait 30 minutes for it to go back to sleep.
Long video 33:00
5:43 - charge battery weak battery will cause lots of problems
connect clamp on amp meter
28:46 how to connect multimeter without clamp
/////
At 13:24 in this video the technician measures the voltage drop across a fuse and then
using a lookup table (below) determines the current flowing through that fuse. This is how
He determines which circuit is exhibiting parasitic draw on the battery.
Lookup Table - Amperage through a fuse by measuring the Voltage drop across a fuse:
better table - https://www.powerprobe.com/resource/20240904232955310.pdf
fuse types:
parasitic
Dustin